Visor Finance Unlimited Minting

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Visor Finance

Due to a bug in the Visor Finance smart contract, an attacker was able to mint an unlimited number of VISR tokens. These were then sold on the open market. The Visor Finance project has merged with Gamma Strategies, and all affected users will be issued new GAMMA tokens.

This is a global/international case not involving a specific country.

About Visor Finance

"Visor Finance is a Uniswap based protocol that is specialized in NFT smart vaults for liquidity provisioning. It predicts the DeFi ecosystem where market conditions can unlock liquidity from networks of independent smart vaults."

"Visor allows DeFi participants to utilize NFT Smart Vaults for liquidity provisioning and active liquidity management on Uniswap v3." "Visor's community is thousands strong and is distributed across a variety of channels."

"As @uniswap v3 makes liquidity provision more complicated for the common man, @VisorFinance allows you to compete with professional liquidity providers by pooling peoples liquidity together and dynamically concentrating it around price to maximize returns for you."

"It is the season of giving, and Visor Finance is going all in. Visor allowed an anonymous actor to mint $8.2M in VISR."

"On December 21st 2021 02:29:11 PM UTC a malicious contract drained Visor Finance’s staking contract of 8,812,958 VISR tokens." "Hackers used the IVisor delegateTransferERC20 interface to generate the exploit. The hackers also used the withdrawal function of the staking contract to call for the desired VISR amount. As a result, reliance on an external IVisor delegateTransferERC20 implementation by the caller allowed the exploit to succeed."

"As long as the hacker passes their own contract as “from” and the contract has an Owner() method of msg.sender, then they can mint as many shares as they want to any address using vvisr.mint()."

"The attack was made possible by implementing the IVisor delegateTransferERC20 interface and calling the staking contract’s withdraw function with the desired VISR amount. Dependence on arbitrary IVisor delegateTransferERC20 implementation by caller allowed for the attack to take place."

"The staking contract should not rely on a user provided contract to implement the required transfer function. The staking contract should instead rely on a fixed transfer implementation such as ERC20.transferFrom."

"The attacker transferred ownership of the contract to its own address, before executing the exploit transaction, minting 195k vVISR tokens."

"These were then burned for 8.8M VISR before being swapped via Uniswap v2 for ETH and washed via Tornado Cash in 7 subsequent transactions totalling 113 ETH ($450k) so far."

"Post exploit, VISR’s price witnessed a steep drop amounting to 94 percent. At press time, VISR was trading at the price of $0.054998, with a market cap that stood slightly over $1 million, according to CoinMarketCap data."

"We will only manage funds using contracts audited by tier one audit firms." "We are engaged with both Quantstamp and ConsenSys Diligence for December and January audits and this new staking contract will be included."

"Launching a new token that replaces the old one is confusing if the ticker stays the same. What we have opted to do is replace the old VISR token ticker symbol with the new one. All tokenomics will stay the same and there will be a redemption (from the time of the snapshot) of 1:1 with the new token, including those staked in the vVISR contract and the those staked in Tokemak. We have already begun the process of listing the new token on various registries in order to make sure the new token is visible and recognized by dexes and wallets starting day one. No one should buy VISR as it will not be redeemable for the new token."

"Since the initial grant from Visor in May 2021, Gamma’s team has worked closely with Visor and has made extraordinary progress on defining and becoming the leading active liquidity manager."

"For the past 6 months the Gamma team has worked on all the tooling necessary to interface with position management as well as develop active liquidity strategies managing $25M in TVL and 40+ pairs for both retail LP’s and projects. We have an incredible structure in place that allows us to execute on the most competitive aspect of active liquidity management: the strategies."

"In addition to managing all positions, Gamma also develops and maintains the Active Strategy Framework, Uniswap position discovery for Mainnet, and Optimism and various deployed strategies that are currently active across all pairs."

"Visor is merging with Gamma Strategies." "[W]e have reached unanimous agreement as two teams that the appropriate outcome is to merge the protocol, treasury and personnel with Gamma Strategies." "Tomorrow, Gamma will be providing liquidity for $GAMMA and will be distributing tokens to all VISR, vVISR and tVISR holders at time of snapshot (occurred December 21st)."

"GAMMA token has been minted and all tokens will be distributed to all VISR, vVISR and tVISR holders at time of snapshot within the next 24 hours." "The $GAMMA token has been distributed to all addresses and liquidity has been deployed to Uniswap v3 of identical amounts and price at the time of the snapshot."

This is a global/international case not involving a specific country.

The background of the exchange platform, service, or individuals involved, as it would have been seen or understood at the time of the events.

Include:

• Known history of when and how the service was started.
• What problems does the company or service claim to solve?
• What marketing materials were used by the firm or business?
• Audits performed, and excerpts that may have been included.
• Business registration documents shown (fake or legitimate).
• How were people recruited to participate?
• Public warnings and announcements prior to the event.

Don't Include:

• Any wording which directly states or implies that the business is/was illegitimate, or that a vulnerability existed.
• Anything that wasn't reasonably knowable at the time of the event.

There could be more than one section here. If the same platform is involved with multiple incidents, then it can be linked to a main article page.

The Reality

This sections is included if a case involved deception or information that was unknown at the time. Examples include:

• When the service was actually started (if different than the "official story").
• Who actually ran a service and their own personal history.
• How the service was structured behind the scenes. (For example, there was no "trading bot".)
• Details of what audits reported and how vulnerabilities were missed during auditing.

What Happened

The specific events of the loss and how it came about. What actually happened to cause the loss and some of the events leading up to it.

Key Event Timeline - Visor Finance Unlimited Minting

Date	Event	Description
December 22nd, 2021 12:00:00 AM	Main Event	Expand this into a brief description of what happened and the impact. If multiple lines are necessary, add them here.

Total Amount Lost

The total amount lost has been estimated at $8,200,000 USD.

How much was lost and how was it calculated? If there are conflicting reports, which are accurate and where does the discrepancy lie?

Immediate Reactions

How did the various parties involved (firm, platform, management, and/or affected individual(s)) deal with the events? Were services shut down? Were announcements made? Were groups formed?

Ultimate Outcome

What was the end result? Was any investigation done? Were any individuals prosecuted? Was there a lawsuit? Was any tracing done?

Total Amount Recovered

There do not appear to have been any funds recovered in this case.

What funds were recovered? What funds were reimbursed for those affected users?

Ongoing Developments

What parts of this case are still remaining to be concluded?

Prevention Policies

In general, complex smart contract hot wallets shouldn't be in charge of minting. Instead, this should always be the responsibility of a simple multi-sig wallet with cold storage keys held by trusted individuals. If a hot wallet is needed for distribution, that should be audited by two competent firms and never exceed a value which the project can self-insure from other liquid assets.